“Our government rewards corporations for shipping jobs overseas, and Jaime Herrera supports them,” says an ad in the 3rd Congressional District. The ad shows a loaded containership steaming away, as if each box had a job in it.

At the ad’s end, the Democratic candidate says, “I’m Denny Heck and I approved this message.”

What kind of message is this? The ad implies that Washington’s 8.8 percent unemployment rate is caused by “shipping jobs overseas.” That is false. The jobs were lost in the recession, which caused job losses overseas as well. The recession was not caused by outsourcing.

These ads also not-so-subtly accuse Republicans of disloyalty. The national Democratic Party, which originated the ads, has chosen this moment in the Obama presidency to blame joblessness on foreigners and on Americans who invest abroad.

In Herrera’s case, they hang the accusation on her pledge not to vote for tax increases. Figure that one out.

In the case of sitting Republicans — and this theme is being used all over the country — the accusation is based on their opposition to the politically named “Creating American Jobs and Ending Offshoring Act,” Senate Bill 3816. This bill has been pushed for 18 years by Sen. Byron Dorgan of North Dakota, a state that imports and exports almost nothing. It came up in the Senate on Sept. 28 and fell seven votes short of passing. Both senators from The Most Trade-Dependent State voted for it.

The bill would have changed the rule that a company pays taxes where it operates. The new BMW carbon-fiber plant in Moses Lake will pay taxes to United States. Ford-Werke AG in Cologne pays U.S. taxes on operating income in Germany only if it sends the money to the United States. Otherwise it pays taxes to Germany. This is a common-sense rule, and has been in the tax code since the Kennedy administration.

The bill wanted to say that if Ford of Germany sold a car to the United States, it would immediately pay U.S. taxes on the profit from that car. But Volkswagen, BMW and Daimler Benz could sell German-made cars here, and not pay the same tax.

Such a rule “puts the United States at a competitive disadvantage,” said Sen. Max Baucus of Montana. Baucus is one of five Democrats who voted against the bill. He is also, as chairman of the Senate Finance Committee and of Congress’ Joint Committee on Taxation, his party’s point man on taxes.

The ranking Republican on Senate Finance, Iowa Sen. Chuck Grassley, was probably right when he suggested, in the midst of a long speech that took Dorgan’s bill seriously, that it “was motivated by politics rather than policy.” In other words, for some who voted yes — and I hope that includes our two senators — the outsourcing bill wasn’t meant to pass. It was meant to provide cover for protectionist TV ads to be used against Rossi, Herrera and other Republicans.

Why did the five Democrats vote against the Dorgan bill? One clue might be that none of the five was up for re-election. They didn’t need the ads.

There are plenty of vile ads this year, and the Democrats have no monopoly of them. But in this state, which lives by international trade, their ads on “shipping jobs overseas” stand out as some of the worst.